U.S. Pat. Nos. 2,915,765; 3,096,531; and 3,141,183 are illustrative of machines for clamping the heel portion of an upper against the corresponding portion of a form while a shoe assembly comprised of the form and the upper mounted thereon is supported in position to be clamped. The clamping is effected by a clamp pad having a pair of legs extending divergently from a bight with the pad bight being caused to bear against the heel end extremity of the upper and the pad legs being caused to bear against the sides of the heel portion of the upper.